In the past, various devices have been implemented for field joining of pipe. U.S. Pat. No. 4,286,914 discloses a means and method for connecting large pipe. The '914 patent discloses a self-propelled vehicle having a pair of grappling devices supported from the vehicle and powered by an operating device. The vehicle, while maintaining an elongated pipe within the grappling device, moves in a horizontal direction to connect the held pipe with previously laid pipe. While the vehicle moves toward the previously laid pipe, the carried pipe may be moved to the left or right simultaneously or simultaneously raised or lowered to align it with the previously laid pipe. When slip joint pipe is being laid, it may be forcibly connected to the previously laid pipe by the kinetics of the vehicle. When slip joint pipe is laid, no other means need be used to keep the pipes fastened together other than the frictional force caused by the forcible insertion of one pipe in another. The vehicle described in the U.S. Pat. No. 914 patent has limited application for use with welded pipe.
U.S. Pat. No. 3,598,347 discloses a side boom tractor to which is mounted a welder. The two sections to be joined are manually placed in position on a pile of timbers. The welder located at the end of the side boom is adjustable for placement over the joint formed between the two pipe sections which have previously been balanced on temporary supports.
U.S. Pat. No. 3,744,259 illustrates a machine designed for laying large diameter pipe over rough terrain in extreme climates. The machine was used for laying 48 inch steel pipe on the Alaska pipeline. The machine comprises an elongated enclosed vehicle which straddles a ditch in which the pipe is to be laid. The housing is supported in each of the corners by pillars in order to maintain the housing level. The pipe is supported through the housing on carriages which are free to float from side to side and up and down. The pipe is constructed with all its bends and crooks over the support position and the house follows the ditch providing a warm environment for the workmen. A deck section follows the carriages up and down so that the workers have a platform which is always maintained at a fixed position relative to the pipe. As the vehicle moves forward out from under the pipe, the pipe is lowered by a series of trailing roller jacks. A sleeve surrounds the pipe as it leaves the vehicle so that the temperature of the pipe is gradually changed from the relatively warm temperature to the frigid arctic temperature. This machine is a special use vehicle for frigid conditions and is extremely long and thereby has limited functions in rough terrain such as jungle areas.
U.S. Pat. No. 4,591,294 discloses in FIG. 8 a self-propelled platform supported on large diameter wide-tired twin-wheels at the front and rear ends and also at the center. The wheels are independently suspended and independently driven and steered. A crane is mounted on the vehicle for loading pipes from transport trucks onto a pipe storage area 83 immediately behind the crane. The pipe lengths are fed from the storage area to welding assembly 42 which is mounted toward the rear of the vehicle. Crawler tracks are used under the welding assembly when the vehicle crosses rough terrain. The tracks can be raised out of contact with the ground when not required. At the completion of the welded joint, the whole vehicle moves forward a sufficient distance to bring the next joint to be welded into the welding assembly.
U.S. Pat. No. 3,984,007 discloses a pipe handling apparatus for pipe laying barges. The pipe is lifted from an incoming pipe conveyor to a transverse rack from one rack position to another and from the rack to the pipe lineup conveyors by a series of pivotal lifting means which lift, move, and deposit the pipe without impact or shock, whereby the pipe and any concrete or other coating on the pipe is not damaged. The '007 patent also discloses a universally adjustable lineup conveyor apparatus.
In the past, and presently, for pipelines that are being installed in fairly wide open spaces, it has been desirable to perform as many pipeline welds under controlled shop conditions and ship the longest lengths practicable to the pipeline ditch site for final welding. However, problems have arisen in inaccessible terrains such as jungles and mountainous regions where access has been a problem. In those situations, it is still desirable to perform as many pipeline welds as possible under conditions which closely resemble those found in a fabrication shop. In remote and inaccessible areas, it is impracticable to join several lengths of pipe together since such long segments of pipe would not be easily transportable to the pipeline right of way. Thus, in the past, for pipelines in inaccessible locations, there have been no attempts to connect two or three pipe lengths together when shipped to the closest port of call to the pipeline right-of-way. Instead, individual lengths, each about 12 meters long, are shipped to the right-of-way for field joining each length to the next adjacent length.
It is the object of this invention to provide a vehicle which is compact in design and, therefore, capable of being transported to the pipeline right-of-way even in remote locations with very limited acessibility.
It is a further object of this invention to provide an apparatus which can be parked along the pipeline right-of-way at a point approximately in the middle of that day's production along the pipeline for making, on a continuous basis, joints between two sections of pipe which will then be strung along the right-of-way for subsequent welding into the pipeline.
It is a further object of this invention to provide a light-weight apparatus which can be brought into remote and inaccessible areas and which is fully self-contained and capable of continuous welding of pairs of pipe sections to each other.